JRuby 10.1.1.0 is released, with a bunch of compat fixes, more performance work, and several third-party CVEs resolved. JRuby 10.1 is our active development branch, with 10.0 being stable. Upgrading is recommended if you want the latest and greatest! www.jruby.org/2026/07/22/j...

Our friends over at @fastruby.io have posted a nice compatibility matrix for JRuby versions, covering Ruby and Rails compatibility. Check it out to learn how the versions line up or if you haven't already discovered how JRuby can help you run Ruby and Rails better! www.fastruby.io/blog/jruby/r...

JRuby & Rails Compatibility Table - FastRuby.io | Rails Upgrade Service

A complete table showing the compatibility between JRuby and Rails across each version, including the Ruby language level and the Java version that each JRuby line requires.

fastruby.io

JRuby 10.0.6.0 released! Updated jruby-openssl, faster Java interface support, and many other fixes and improvements. JRuby 10.0.x is our LTS version, so upgrading is recommended. www.jruby.org/2026/06/11/j...

JRuby 9.4.15.0 is released! This is the last regularly-scheduled release of JRuby 9.4.x and includes the last set of unreleased 9.4 fixes. Future releases will be done as needed for commercial JRuby users. Contact us if you need long-term JRuby 9.4 support. www.jruby.org/2026/06/08/j...

JRuby 10.1 is released! We've caught up with CRuby 4.0 after less than four months, and pushed a bunch of new optimizations: smaller objects, smaller numerics, and groundwork for many more. We'll maintain 10.0 as our stable line, but do try 10.1 yourself! www.jruby.org/2026/04/21/j...

JRuby 10.0.5.0 is released! This round we fixed some memory leaks when embedding multiple JRuby instances, a few pesky Windows bugs, and several Ruby compatibility blockers. Enjoy! www.jruby.org/2026/04/06/j...

Today we were informed of a low-severity vulnerability in the bcrypt-ruby gem. We worked with the maintainers to arrange a fix. Upgrading is recommended. CVE-2026-33306: Integer Overflow Causes Zero Key-Strengthening Iterations at Cost=31 on JRuby github.com/bcrypt-ruby/...

Integer Overflow Causes Zero Key-Strengthening Iterations at Cost=31 on JRuby

### Impact An integer overflow in the Java BCrypt implementation for JRuby can cause zero iterations in the strengthening loop. Impacted applications must be setting the cost to 31 to see this ...

github.com

JRuby 10.0.4.0 is released! A month after 10.0.3.0, we've addressed lots of one-off issues, a few memory and thread-safety fixes, and general compatibility and stabilization work. Enjoy! www.jruby.org/2026/03/04/j...

JRuby 10.0.3.0 is released! Over 80 issues and pull requests and 13 external contributors combined to help further stabilize our 10.0 series! There's lots of compatibility fixes, a few performance enhancements, and a number of library updates. Upgrade is recommended! www.jruby.org/2026/02/02/j...

New post: Warbled Sidekiq: Zero-install Executable for JVM In my previous post, I showed how to use Warbler to package a simple tool as an executable jar. This post will demonstrate how to “warble” a larger project: the Sidekiq background job server! buff.ly/ZEasNiu

Warbled Sidekiq: Zero-install Executable for JVM

In my previous post, I showed how to use Warbler to package a simple image-processing tool as an executable jar. This post will demonstrate how to “warble” a larger project: the Sidekiq background…

blog.headius.com

New post: "Packaging Ruby Apps with Warbler: Executable JAR Files" Warbler is the JRuby ecosystem’s tool for packaging up Ruby apps with all dependencies in a single deployable file. We’ve just released an update, so let’s use Warbler to create all-in-one packaged Ruby apps! buff.ly/ZdXcCop

Packaging Ruby Apps with Warbler: Executable JAR Files

Warbler is the JRuby ecosystem’s tool for packaging up Ruby apps with all dependencies in a single deployable file. We’ve just released an update, so let’s explore how to use Warbler to create…

blog.headius.com

Warbler 2.1.0 has been released! Warbler allows you to package JRuby applications (with obfuscation of code) as a single binary, either a .jar file you can run directly or a .war file you can deploy to any Java application server. Blog post coming! rubygems.org/gems/warbler...

We have published Docker images for JRuby 9.4 and JRuby 10 on JDK 25! The -dev images are also updated to latest commits. Give them a try and let us know if there's any issues!

At the end of my post on JRuby and JDK 25 startup time features, I teased a bit of the unreleased improvements from Project Leyden. It turns out the latest commits improve startup time even more, so it seems worth posting a quick follow-up! www.reddit.com/r/ruby/comme...

From the ruby community on Reddit: JRuby and Leyden: Even Better Startup

Posted by headius - 1 vote and 0 comments

reddit.com

New post: JRuby and JDK 25: Startup Time with AOTCache Let's take a look at JRuby's startup time journey, all the way up to using JDK 25's AOTCache and Project Leyden features coming to a JDK near you soon. blog.headius.com/2025/09/jrub...

JRuby and JDK 25: Startup Time with AOTCache

JDK 25 is the newest LTS release since JDK 21, and it ships with a gaggle of amazing VM-level features. This post will cover one of the most important improvements for command-line ecosystems like…

blog.headius.com

JRuby 9.4.14.0 is released! We've updated a bunch of the standard library (including "cgi" to fix a couple of CVEs), fixed a few memory leaks and a bunch of compatibility issues, and generally stabilized things. Upgrading is recommended! www.jruby.org/2025/08/28/j...

JRuby 10.0.2.0 is released! This is a small release to fix an ArgumentError regression in JRuby 10.0.1.0 plus a few other small fixes. Recommended upgrade for all, but let us know if you run into any issues! www.jruby.org/2025/08/07/j...

We have just released JRuby 10.0.1.0, our first update to JRuby 10! There's dozens of patches including full support (finally) for Zeitwerk and a bunch of Ruby 3.4 language fixes. Upgrade today and let us know how it goes! www.jruby.org/2025/07/17/j...

We have released jruby-maven-plugins 3.0.6, which updates JRuby to 9.4.13.0 along with several other improvements. But more exciting: Warbler is BACK! We've updated it for latest JRuby and dependencies and it's running green in CI. Time for feature requests! github.com/jruby/warble...

Updating and releasing with modern libs · Issue #558 · jruby/warbler

It's been too long since this library had an update and release. This issue will track the tasks necessary. I cloned and ran tests locally with JRuby 10, and a number of areas need improvement: Lot...

github.com

FYI: now that Ubuntu 20.04 is EOL, future releases of the JRuby Docker image will be based on Ubuntu 22.04. This will take effect with releases 9.4.14.0 and 10.0.1.0, whenever they happen. See github.com/docker-libra...

Update Ubuntu 2025-06-01 by ROCKsBot · Pull Request #19167 · docker-library/official-images

Update Ubuntu to the latest published OCI tarballs as of 2025-06-01.

github.com

JRuby 9.4.13.0 is released! We have fixed several user issues, including a slow leak in Java interface implementation, a possible deadlock between JIT and main threads, and backported launcher improvements from JRuby 10! www.jruby.org/2025/06/10/j...

this week on the unikernel application spotlight we check out @jrubyproject.bsky.social www.youtube.com/watch?v=72wl... - real threads && jvm interop - congrats on 10.x release and 24 yrs! @headius.bsky.social

[Unikernel Application Spotlight] JRuby

YouTube video by nanovms

youtube.com

Security advisory: We have released jruby-openssl gem 0.15.4, jruby 10.0.0.1, and jruby 9.4.12.1 to address CVE-2025-46551, disabled hostname verification by default. We recommend that all users upgrade! www.cve.org/CVERecord?id... www.jruby.org/2025/05/07/j... www.jruby.org/2025/05/07/j...

Seems like a few folks didn't think my 2D bar chart was "beautiful", so let's kick it up a notch with 3D, SVG, and PDF generation using the same JFreeChart family of libraries! blog.headius.com/2025/05/3d-c...

3D Charts and More with JRuby and JFreeChart

After playing with JFreeChart and JRuby and writing up a lovely blog post called “Beautiful Charts with JRuby and JFreeChart” it seems that some folks did not agree with my assessment of the charts…

blog.headius.com

It's finally here! JRuby 10 has been released with support for Ruby 3.4 (including 3.2 and 3.3 updates as well). Minimum Java version has been bumped up to Java 21, allowing us to support modern JVM features. Check out the release notes and start migrating today! www.jruby.org/2025/04/14/j...

It's almost time! I've just published my first post on JRuby 10, "Part 1: What's New". More posts will follow in the coming weeks, but JRuby 10 itself should be generally available before my RubyKaigi talk next week!

JRuby 10, Part 1: What's New

I am very excited to introduce you to JRuby 10, our biggest leap forward since “JRuby 9000” was released almost a decade ago.

buff.ly

We have released jruby-launcher 2.0! This version eliminates the old C++ code in favor of two options: * On Unix systems, the launcher will exec the already-present jruby.sh script. * On Windows, we have a new Rust-based exe coming soon. Let us know if you have any issues:

GitHub - jruby/jruby-launcher: JRuby's native launcher executable

JRuby's native launcher executable. Contribute to jruby/jruby-launcher development by creating an account on GitHub.

buff.ly

JRuby 10 HEAD builds are now live in GitHub Actions setup-ruby and for any local Ruby installers that depend on jruby-dev-builder's jruby-head packages! Fingers crossed it doesn't cause too many problems, but let us know right away if something goes awry!

I just took pdf-reader for a spin on v10-SNAPSHOT, all green first try github.com/yob/pdf-read...

Run tests on pre-release of jruby 10 by yob · Pull Request #552 · yob/pdf-reader

There's no jruby:10 image on docker hub yet, but seems like it's a work in progress at https://github.com/jruby/docker-jruby I grabbed a Dockerfile from there and vendored it for now

github.com

Calling all Rubyists! We are looking for help verifying third-party libraries on JRuby 10! I've opened an issue to track that process, and provided links to snapshot JRuby builds you can use to verify your own code. Please help us verify JRuby 10!

Check third-party libraries against JRuby 10 · Issue #8675 · jruby/jruby

We are about to switch master and jruby-head to JRuby 10, but want to try to make sure that third-party libraries testing against jruby-head do not suddenly fail. To that end, we would like to repr...

buff.ly